html,body{height: 100%;}
body{background-color: snow;}
li{
	float: left;
	list-style: none;
	padding: 20px;
}
a{
	color: #000;
	font-size: 22px;
	text-decoration: none;
	padding-bottom: 5px;
	border-bottom: 1px dotted #999;
}
h1{
	font-family: 'MJXc-TeX';
}
a:hover{
	border-bottom: none;
}
.nav a{
	border-bottom: none;
}
.clearfix:after{
	content: "";
	display: block;
	clear: both;
}
.div_line{
	width: 90%;
	margin: 0 auto;
	height: 1px;
	background-color: #000;
}
.div_line_gray{
	width: 90%;
	margin: 0 auto;
	height: 1px;
	background-color: #eee;
}
.content{
	width: 70%;
	height: 100%;
	margin: 0 auto;
	border: 1px dotted #eee;
	text-align: center;
}
.ul_content li span{
	display: inline-block;
	margin-left: 120px;
}